Serotype distribution, antibiotic resistance, multilocus sequence typing, and virulence factors of invasive and non-invasive Streptococcus pneumoniae in Northeast China from 2000 to 2021.

Streptococcus pneumoniae infection is a major public health concern with high morbidity and mortality rates. This study aimed to evaluate the serotype distribution, antimicrobial resistance changes, clonal composition, and virulence factors of S. pneumoniae isolates causing pneumococcal disease in northeast China from 2000 to 2021. A total of 1,454 S. pneumoniae isolates were included, with 568 invasive strains and 886 non-invasive strains. The patients from whom the S. pneumoniae were isolated ranged in age from 26 days to 95 years, with those ≤ 5 years old comprising the largest group (67.19%). 19 F, 19 A, 23 F, 14, and 6B were the most common serotypes, of which 19 A and 19 F were the main serotypes of invasive and non-invasive S. pneumoniae, respectively. CC271 was the most common multilocus sequence type. Serotype 14 had the lowest expression of cbpA, rrgA, and psrP genes, but expression levels of 19 A and 19 F genes were similar. All isolates were sensitive to ertapenem, moxifloxacin, linezolid, and vancomycin but highly resistant to macrolides, tetracyclines, and cotrimoxazole. Simultaneous resistance to erythromycin, clindamycin, tetracyclines, and trimethoprim/sulfamethoxazole was common pattern among multidrug-resistant isolates. Non-invasive S. pneumoniae had higher resistance to ß-lactam antibiotics than invasive strains. 19 A and 19 F were the main strains of penicillin-resistant S. pneumoniae. The resistance rate of ß-lactam antibiotics decreased from 2017 to 2021 compared to previous periods. Including PCV13 in the national immunization program can reduce the morbidity and mortality rates of pneumococcal disease effectively.

Characterization of Streptococcus pneumoniae Macrolide Resistance and Its Mechanism in Northeast China over a 20-Year Period.

Due to the resistance of Streptococcus pneumoniae to ß-lactams, macrolides, and tetracyclines, treatment alternatives have become increasingly limited worldwide. We aim to describe the characterization of erythromycin-resistant S. pneumoniae (ERSP) strains in northeastern China over a period of 20 years. A total of 1,240 ERSP strains were collected and classified into five groups based on the ages of the patients. Etest strips and Kirby-Bauer disk diffusion were performed for drug susceptibility testing. The capsule swelling test was used for capsule typing. The phenotype of drug resistance was detected by the erythromycin and clindamycin double-disk method. The ermB, ermTR, mefA, and tetM genes were detected by PCR. Among the 1,240 ERSP strains, 510 were invasive isolates, and 730 were noninvasive isolates. The results of drug susceptibility testing showed that the rates of resistance to penicillin, amoxicillin, cefotaxime, ceftriaxone, meropenem, tetracycline, trimethoprim-sulfamethoxazole, and chloramphenicol varied among the different age groups. 19F, 19A, 23F, 14, and 6B were the serotypes that were commonly found among ERSP strains. Among all strains, 99.03% (1,228/1,240) exhibited an MLSB (macrolide-lincosamide-streptogramin B) resistance phenotype, of which 1,221 strains displayed a constitutive MLSB (cMLSB) phenotype and 7 strains showed an inducible MLSB (iMLSB) phenotype. All of these strains carried the ermB gene. In contrast, only 0.97% of strains of M phenotypes were found to carry the mefA gene. Both the ermB and mefA genes were detected in 704 strains that exhibited multidrug resistance, whereas the ermTR gene was not detected. Furthermore, 1,185 tetracycline-resistant strains were found to carry the tetM gene. Macrolide antimicrobial drugs should be used cautiously for the empirical treatment of S. pneumoniae infections. IMPORTANCE This study presents a retrospective analysis using 1,240 clinical erythromycin-resistant Streptococcus pneumoniae (ERSP) isolates collected in northeastern China between January 2000 and December 2019. The serotype distribution, corresponding vaccine coverage, as well as resistance phenotypes, genes, and mechanisms to macrolide and tetracycline of these isolates were systematically described, analyzed, and discussed. We hope that this study will inform clinicians in their respective regions when selecting antimicrobial agents. We also hope that this study is useful for researchers in related fields. Finally, we emphasize in this study that vaccination is the best preventive measure for S. pneumoniae infection considering its resistance to commonly used antibiotics. The determination of the S. pneumoniae serotype distribution also provides valuable empirical evidence for local health authorities when introducing appropriate vaccines in a specific area.

Prevalence of microorganisms co-infections in human papillomaviruses infected women in Northern China.

PURPOSE: Due to scarce data on the prevalence of genital microorganism infections among individuals with human papillomavirus (HPV) infections, the present study aimed to evaluate microorganism co-infections and associated risk factors in HPV-infected women in Northern China. METHODS: Cervical samples of 4290 enrolled female patients were collected to detect HPV, bacterial and yeast infections in gynecologic outpatients. Serum samples collected were analyzed for the presence of serological markers for human immunodeficiency virus (HIV), hepatitis B (HBV) and hepatitis C (HCV) and Treponema pallidum infections. HPV typing was carried out by polymerase chain reaction and flow-through hybridization on cervical brush specimens. Chlamydia trachomatis was identified by strand displacement amplification, and other microorganisms were detected by conventional methods. Odds ratio of co-infection was assessed between HPV-positive and -negative patients. RESULTS: Overall, co-infections among HPV-infected patients showed a trend for risk compared with HPV-negative patients. In this cross-sectional study on 4290 female outpatients, statistical analyses revealed a significant association between HPV and detection of anti-HBV antibodies, bacterial vaginosis, C. trachomatis and Ureaplasma urealyticum; no correlation was found between HPV infection and anti-HIV, anti-HCV, T. pallidum, Trichomonas vaginalis and Neisseria gonorrhoeae, which were detected only in few cases among either HPV-positive or -negative patients. CONCLUSION: The study demonstrated a significant association between HPV and HBV, bacterial vaginosis, C. trachomatis and U. urealyticum. The study results suggest that it may be important to screen for the simultaneous presence of different microorganism co-infections with HPV that may have synergistic pathological effects.

[High-throughput genotyping multiplex ligation-dependent probe amplification for assisting diagnosis in a case of anti-Di(a)-induced severe hemolytic disease of the newborn].

OBJECTIVE: To report a rare case of hemolytic disease of the newborn (HDN) with kernicterus caused by anti-Di(a) diagnosed using high-throughput genotyping multiplex ligation-dependent probe amplification (MLPA). METHODS: Conventional serological methods were used to detect the antibodies related with HDN. The genotypes of more than 40 red blood cell antigens for the newborn and her parents were obtained using the high-throughput MLPA assay. The antibody titers were tested using a standard serological method. RESULTS: The unknown antibody against the low-frequency antigens was predicted based on the primary serological tests. The genotyping results for more than 40 red blood cell antigens of the newborn and her parents showed incompatible antigens of MNS and Diego blood group system, indicating the existence of anti-N or anti-Di(a). Further serological tests confirmed anti-Di(a) existence in the plasma of the newborn and her mother. The titer of anti-Di(a) in the mother's plasma was 1:32. CONCLUSION: Severe HDN including kernicterus can result from anti-Di(a). High-throughput genotyping MLPA assay can help type some rare antigens in complicated cases. The reagent red cell panels including Di(a)-positive cells are necessary in routine antibody screening test in Chinese population.

[Analysis on the characteristics of blood serum Ab-IgG detective result of severe acute respiratory syndrome patients in Guangzhou, China].

OBJECTIVE: To probe blood serum Ab-IgG characteristics of severe acute respiratory syndrome (SARS) patients in Guangzhou and investigate the related factors. METHODS: The serum of such population diagnosed as SARS convalescent patients, non-SARS patients, family consanguineous contraction persons, wild animal and vegetable salesman and community common people was collected. The lab detective method of ELISA was adopted for these serum samples. And the epidemic investigations for the SARS patients were also carried out. RESULTS: Of these populations, the detective rate of Ab-IgG for the clinic diagnosed SARS patients, which was 53.7%; That for the wild animal salesman and community common people were 16.7% and 0.9%, respectively. Among the clinic diagnosed SARS patients, the positive antibody detective rate was 90.4% for those which had specific contact history or infectivity, which was higher than that for other population. Among the specific contact history or infectivity cases, the antibody positive rate for the young and the old was lower than that for the adult. Meanwhile the difference did not exist among other cases. The antibody positive rate was identical between the male and the female. And the antibody detective rate was decreased by the month. CONCLUSION: As a whole SARS-CoV Ab-IgG detective rate for the clinic diagnosed SARS patients was 53.7% only. The reasons for that mainly lie in the wrong clinic diagnosis besides these factors such as age, hormone use and reagent and so on. The combination of lab detection results and epidemic investigation was propitious to the diagnosis veracity. It was impossible for the sub-clinic infection of SARS-CoV virus. The importance in the virus transmitting course need to be further studied.

[Discoveries of avian influenza A(H9N2) virus in chickens and men infected by H9N2 virus in Guangzhou area].

OBJECTIVE: To understand the epidemic status of avian influenza A virus in chickens and men in Guangzhou area and to prevent men suffering from avian influenza A (H5N1) virus. METHODS: Etiologic and serological surveys were conducted in chickens and men who were working in the poultry farms and slaughter house. Viruses were isolated with both MDCK cells and embryonated chicken eggs. Hemagglutination inhibition tests were performed by routine method. RESULTS: Anti-H9N2 antibody was found in 12.8% of the chickens and 5.1% of the workers. CONCLUSIONS: Avian influenza virus H9N2 subtype existed in chickens and this subtype of influenza A virus might infect men.